微波固相法制备铁酸锌脱硫剂的硫化动力学

Sulfurization kinetics of zinc ferrite sorbent prepared by microwave solid-state method

通过微波与常规固相法制备了铁酸锌高温煤气脱硫剂,使用X射线衍射(XRD)、氮吸附、扫描电子显微镜(SEM)以及X射线光电子能谱(XPS)对两种不同焙烧方式制备的脱硫剂的物相组成、织构形貌和表面元素进行了表征。数据显示微波焙烧制备的脱硫剂具有孔隙结构丰富、表面金属元素含量高、结合能低等优点。使用热天平对铁酸锌脱硫剂硫化行为进行了研究,根据等效粒子模型计算了两种脱硫剂与硫化氢气体反应的动力学参数,得到了硫化反应动力学方程,并在固定床上对其煤气脱硫性能进行了考察。结果表明硫化过程分为化学反应控制区和颗粒内扩散控制区。微波焙烧制备脱硫剂的化学反应活化能和颗粒内扩散活化能较低,说明其在硫化氢气体脱除上具有更高的活性。在模拟煤气气氛下,相比常规焙烧方法制备的脱硫剂,微波制备的脱硫剂的脱硫性能显著提高,具有更高的硫容和更长的精脱硫时间。

Zinc ferrite high temperature desulfurization sorbents were prepared by microwave and conventional solid-state method., X-ray diffraction（XRD）, N2 adsorption, scanning electron microscope（SEM） and X-ray photoelectron spectroscopy（XPS） were used to characterized the phase composition, morphology texture and surface elements of the sorbents prepared by two different methods. The date revealed that the sorbent prepared by microwave features abundance of pore structure, high content and low binding energy of metal element on the surface. The sulfurization behavior of sorbents were investigated on thermal analysis balance. The kinetics parameters of reaction between sorbents and H2 S gas were calculated based on equivalent grain model and the kinetics equations of sulfurization reaction were obtained. The performance of coal gas desulfurization were tested on a fixed bed. The results showed that the sulfurization process was divide into two regions which were chemical reaction control region and intraparticle diffusion control region. The sorbent heated by microwave occupied lower chemical reaction activation energy and intraparticle diffusion activation energy, indicating that it had higher reactivity on the removal of H2 S gas. In the environment of simulated coal gas, the desulfurization performance of sorbent prepared by microwave had a significant improvement with higher sulfur capacity and longer deep desulfurization time as compared with that of sorbent prepared by conventional method.